Sawhorse toggle clamp



United States Patent SAWHORSE TOGGLE CLAMP Robert L. Chesney, LosAngeles, Calif., assignor, by mesne This invention relates toimprovements in trestles, e. g. sawhorses, and more particularly to adevice for securing legs to a cross piece to form a trestle.

-It is an object of this invention to provide a trestle, which can bereadily set up as a sturdy and substantially rigid supporting structure,and which can be knocked down easily and quickly to facilitate storageand transportation thereof.

. Another object of the invention is to provide a new and improveddevice having a toggle joint construction for securing and locking legsto a cross piece to form a trestle.

A further object of the invention is to provide a clamp ing device ofthe above mentioned character, which is rugged and simple inconstruction and which because of its simplicity in construction can beproduced inexpensively with a view to supplying an eflicient clampingdevice for trestles at small cost.

Further objects and advantages of the invention will become apparentduring the course of the following part of this specification, whereinthe details of construction and mode of operation of a preferredembodiment thereof are described with reference to the accompanyingdrawing, wherein:

Figure No. l is a perspective view of a portion of a sawhorse, in whichthe legs thereof are secured to a cross piece by means of a toggle clampembodying my invention;

Figure No. 2 is an end elevation on an enlarged scale of a portion ofthe sawhorse, showing certain details of construction of the toggleclamp;

Figure No. 3 is a side elevation of the clamp, as taken on line 33 ofFigure 2; and

Figure No. 4 is a bottom plan view of the clamp in extended position,taken on line 4-4 of Figure 2.

Referring to the drawings more in detail, reference numeral 10designates a sawhorse comprising a horizontal cross piece 11, two legs12 and 13, and a clamp 14 which releasably secures the legs to the crosspiece. The cross piece and the legs of the illustrated embodiment arepieces of lumber of rectangular cross sections. In cases where it isdesired to construct a sawhorse of the type as is generally used bycarpenters, it will be found that two by fours serve well for the legsand cross piece.

The clamp 14 comprises two channels 16 and 17 which serve as sockets forthe ends of legs 12 and 13 respectively. The channels are formedpreferably from sheet steel, or other suitable material, and aresubstantially similar to each other in size and shape, whereby adescription of the details of one is applicable to the other. Thus, thedetails of construction of channel 17 are described hereinafter and thereference numerals which designate respective component parts of channel17 are used again to designate like parts of channel 16; however, in thecase of channel 16 a prime is applied to the reference numerals thereof.Channel 17 is shaped by bending the sheet from which it is formed, alongparallel lines 18 and ice 19, to define a bottom wall 20 for the channeland two side walls 21 and 22, extending in respective planessubstantially at right angles to the bottom wall. The side walls 21 and22 are similar to each other in size and form and, therefore, thedetails of construction of but one such side wall are described. Thus,side wall 21 has a pair of spaced apart slits 24 and 25, cut inwardlyfrom its longitudinal edge to provide a free portion between the slits.This portion is bent inwardly as on line 27, to form a flange 28 forholding a leg of the sawhorse straight within the channel.

Adjacent to slit 24 is an ear 30 providing a means for pivotallyattaching the channel 17, as with a rivet or pin 31, to a correspondingcar 30' on the channel 16. The ear 30 is set back from the plane of theside wall 21, by an offset 32, so that the surfaces between thepivotally connected ears 30 and 30' will lie flush against each other.

That portion of the channel extending upwardly beyond the ear 30, forconvenience in description, is referred to as a jawfor the clamp. Asbest shown in Figure No. 2 of the drawing, the clamping edge for suchjaw is defined by a notch 34 which receives the cross piece betweenopposite jaws of the clamp. Each notch is defined by the upper edge 35of the ear 30, and edge portions 36, 37, and 38. The edge portion 36 isdisposed at an angle with respect to the plane of bottom wall 20 suchthat when the channels are spread apart the edge '36 will be disposed ina horizontal plane, thereby forming a rest for the under surface of thecross piece. The edge portion 37 extends upwardly from the edge portion36 and at right angles thereto, so that when the clamp is secured to thecross piece, the edge 37 will lie in a vertical plane against a sideface of the cross piece. Edge portion 38 is inclined from its point ofintersection with edge 37 away from the bottom wall 20 of the channel todefine a tooth 39 which cuts into the cross piece when the clamp isexpanded, as is described more fully hereinafter. v

In the bottom wall of the channel there is a lug 41 struck from thebottom wall, with one side of the lug remaining integral with the bottomWall. The lug is bent inwardly of the channel and extends substantiallyat right angles to the bottom wall, thereby serving as a stop againstwhich the top end face of leg 13 abuts when the leg is fitted into thechannel. The line on which the lug 41 is bent lies in a plane whichextends substantially perpendicular to bottom wall 20 and contains thepoints 42 at which the edges 36 and 37 intersect. Thus, when a leg forthe sawhorse is fitted into the channel, the leg will extend up to thepoints 42, 42' on respective side walls of the channel, whereby thecross piece 11 rests on and is supported by the leg. Also struck fromthe bottom wall 20 and bent inwardly of the channel are two projectingteeth 43, which serve to bite into an end edge of the leg 13 to securethe leg within the channel.

As thus far described it is apparent that the clamp of this inventionoperates as a pincers. When the channels are spread apart at their lowerends the jaw-s thereof move toward each other to cut into the crosspiece of the sawhorse. In order to function satisfactorily, a sawhorsemust be of sturdy and rigid construction, and to this end, the clamp ofthis invention is so designed that its jaws may be forced togethereasily and simply to bite into the cross piece of the sawhorse andfirmly grip it,- and the clamp holds the legs of the sawhorse securelyin their respective channels of the clamp, thereby tightly securing thelegs to the cross piece. Furthermore, the clamp of this invention isdesigned to become locked when spread to its clamping position so thatthe legs and cross piecemay not inadvertently become loose from eachother. In addition to these advantageous characteristics the clamp isadapted to be made loose quickly so as to permit easy disassembly of thesawhorse when desired.

of the channels such that the clamp forms an A-frarne type of structurewhen the sawhorse is assembled.

The plate 45 is substantially rectangular in shape and has two side arms46 and 46 integral with opposite ends of the plate and bent upwardlyfrom the plane of the 'plate so as to lie in respective planes at rightangles to the plate. These side arms extend beyond the line of a sideedge 47 of the plate and are pivotally secured at their outer ends onthe outside faces of respective side wallsof channel 17 as with a pin orrivet such as that designated by numeral 48. The plate 45 is attached tothe other channel 16 by means of a pair of links, one of which is shownat 49. One end of link 49 is pivotally secured by pin 50 to the outsideface of a side wall of channel 16, and the other end of the link ispivotally secured to the arm 46 by a pin 51.

The plate 45 is of suflicient length to extend beyond the links 49 andthus the end edges of the plate strike against the links to prevent theplate from swinging upwardly past the links when the channels are spreadapart to their outer limit. The pin 51 is spaced above the plate 45 by adistance which is greater than the distance of the pins 48 and 50 abovethe plate. Thus in spreading the channels apart the plate is swung onits pivots 48 until it strikes against the bottom edges of the links 49,whereupon the center of pin 51 will have become positioned slightlyabove a line passing through the centers of pins 48 and 50, i. e. thepin 51 becomes positioned past center of the pins 48 and 50, therebylocking the channels of the clamp in their spread apart position.Locking of the clamp is made more secure by engagement of a dimple 52,projecting inwardly from the side arm 46, with a depression or slot 53formed in the outside face of the link 49.

The hinge or pivoted joint at the pin 51 constitutes a knee for thetoggle joint of the clamp. The plate 45 as viewed in Figure 2, extendsleftwardly of such knee and thus provides a convenient handle forapplying force to the knee to close or open the jaws of the clamp.Strengthening ribs such as those shown at 55 are preferably formed inthe plate to resist bending of the plate.

Each side wall of each channel has a lever arm pivotally secured theretoand of sufiicient length to extend into respective channels for grippingthe legs of the sawhorse and thereby rigidly holding the legs in placein the channels. Such lever arms are shown at 57 and 57'. The arm 57 issecured to side wall 21 by a pivot pin 58 and the arm 57 is secured to acorresponding side wall of channel 16 as with pivot pin 58'. At their adjoining ends the lever arms are secured together by a pivot pin 59. Theopposite ends of the lever arms project into their respective channelsand are pointed as designated at 60 whereby they bite into the legs ofthe sawhorse or become wedged tightly against the side faces of the legsto hold the legs firmly within the channels when the channels are spreadapart by operating the plate handle 45 of the toggle joint. The leverarms are set back inwardly from the planes of their respective channelside walls by means of joggles such as designated at 61-61'.

For purposes of economy in materials, the lever arms and the links 49may be blanked out from the bottom walls of the channels, leaving voids63 in such bottom wall.

To construct a sawhorse with clamps as provided by this invention, across piece of desired length and width is placed on a floor and a clampis positioned on the cross piece with the jaws of the clamp extendingdownwardly along opposite side faces of the cross piece. An

operator then inserts a leg into each channel of the clamp and pushesdownwardly on the legs until their end faces abut against the lugs 41 inthe channels. Such downward force on the legs causes the teeth 43 to cutinto the end edges of the legs adjacent the bottom walls of therespective channels, and the wood of the legs is thereby bulgedoutwardly into the openings in the bottom walls 20, from which the teethare bent. The teeth 43 thus serve to hold the inner ends of the legssecurely in their respective channels. To prevent the teeth 43 frombeing bent further inwardly of the channels by the force exertedlongitudinally on the legs, the teeth are bent from the bottom walls 20at an angle of approximately 10 from their respective bottom walls andthus they cut into the legs in a direction essentially longitudinal ofthe legs.

With the legs thus extending upwardly from the cross piece, the operatorspreads the legs apart and presses down on the handle or plate of thetoggle joint as with his foot, to close the jaws of the clamp againstopposite side faces of the cross piece so that teeth 39 of the jaws willcut into the cross piece. In this operation the legs become wedgedtogether along their inside end edges, whereby they cooperate as aunitary structure for supporting the cross piece and are furthertightened in the channels. Spreading of the legs also moves the lowerends of the lever arms 57 and 57' apart so that the free ends of thelever arms (points cut into the legs and thereby secure the legs in thechannels. Pressing down on the toggle joint moves the knee of the jointdownwardly past center of the pins 48 and St) to lock the clamp agianstbeing inadvertently released from its grip on the cross piece and thelegs. Engagement of the dimples 52 in the slots 53 assists in holdingthe clamp in its locked position.

To complete the sawhorse, another pair of legs is secured to the crosspiece with a second clamp as in the manner described above. The sawhorseis then ready to be turned upright and put into use.

Dissembly of the sawhorse is simple and easy, requiring merely that thetoggle handles on the clamps be lifted in a direction away from thehinges or pins 31, to open the jaws of the clamps and release the legsfrom the lever arms 57.

The toggle joint construction of the clamp of this invention givesenormous mechanical advantage, and as the clamp is designed so as to beoperated by ones foot if desired, it is adapted to receive a strongforce against the knee of the toggle joint and to translate such forceto a direction such that the jaws of the clamp will cut deeply into thercoss piece and the lever arms will cut deeply into the legs of thesawhorse to insure a tight and sturdy assembly of the legs and crosspiece. It is to be noted, too, that the tight grip of the clamp to thecross piece as is made possible by the toggle joint construction of theclamp, permits the jaws of the clamp to be made relatively short so thattheir ends will be spaced from the top surface of the cross piece. Thus,in using the sawhorse as a support for boards or planks to be sawed, thelikelihood of striking a clamp with a saw and thereby dulling the saw,is greatly reduced.

It is to be understood that the form of my invention, herein shown anddescribed, is a practical and preferred example of the same, and thatchanges may be resorted to within the scope of my invention, which isnot limited to the details disclosed herein but is to be accorded thefull scope of the claims so as to embrace any and all equivalentstructures.

Having described my invention, what I claim as new and desire to secureby Letters Patent is:

l. A clamp for anchoring legs to a cross piece of a trestle, comprisinga pair of channels, each channel having a back wall and a pair of sidewalls, pivot means securing the side walls of one channel to the sidewalls of the other channel, that portion of each channel above saidpivot means constituting a jaw, said jaws being adapted to straddle thecross piece, that portion of each channel below said pivot meansconstituting a socket, said sockets being adapted to receive the legs, apair of arms, means pivotally securing each of said arms to respectiveside walls of one of the channels in the socket portion thereof, a pairof links, each of said links being pivotally secured to respective sidewalls of the other of the channels in the socket portion thereof, pivotmeans securing each of the arms to respective links, a pair of leverarms for each channel, means pivotally securing each of the lever armsintermediate its ends to respective side walls, means pivotally securingthe lever arms of one channel to respective lever arms of the otherchannel, whereby the lever arms project into respective channels forengaging the legs when said socket portions are spread apart.

2. A clamp for anchoring legs to a cross piece of a trestle, comprisinga pair of channels, each channel having a back wall and a pair of sidewalls, first pivot means securing the side walls of one channel to theside walls of the other channel, that portion of each channel above saidpivot means constituting a jaw, each of the jaws having a notch formedtherein for receiving the cross piece between the jaws, said notchesdefining horizontally extending edge portions adapted to lie flushagainst the under face of the cross piece and vertically extending edgeportions adapted to lie flush against respective side faces of the crosspiece, a tooth projecting from each jaw and adapted to cut into thecross piece,

that portion of each channel below said pivot means constituting asocket, said sockets being adapted to receive the legs, a pair of arms,second pivot means securing each of said arms to respective side wallsof one of the channels in the socket portion thereof, a pair of links,third pivot means securing each of said links to respective side wallsof the other of the channels in the socket portion thereof, fourth pivotmeans securing each of the arms to respective links and moveable in adirection away from the said first pivot means and beyond a line passingthrough the said second and third pivot means, a pair of lever arms foreach channel, means pivotally securing each of the lever armsintermediate its ends to respective side walls, fifth pivot meanssecuring the lever arms of one channel to respective lever arms of theother channel and moveable in a direction from said line toward the saidfirst pivot means, whereby the lever arms project into respectivechannels for engaging the said legs when said socket portions are spreadapart.

3. A clamp according to claim 2 and including stop means projectinginwardly from respective back walls of said channels and aligned withrespective intersections of said horizontally extending edges and saidvertically extending edges.

4. A clamp for anchoring legs to a cross piece of a trestle, comprisinga pair of channels, each channel having a back wall and a pair of sidewalls, first pivot means securing the side walls of one channel to theside walls of the other channel, that portion of each channel above saidpivot means constituting a jaw, said jaws being adapted to clamp againstopposite side faces of the cross piece, that portion of each channelbelow said pivot means constituting a socket, said sockets being adaptedto receive end portions of the legs, and toggle joint means positionedbetween said channels and comprising a plate, a pair of arms integralwith the plate and extending in a direction of the plane of the plateand beyond an edge of the plate, second pivot means securing said armsto respective side walls of one of the channels, a pair of links, thirdpivot means securing each of the links to respective side walls of theother of the channels in the socket portion thereof, fourth pivot meanssecuring each of the arms to respective links and moveable in adirection away from the said first pivot means beyond a line passingthrough said second and third pivot means, said plate extendingoutwardly beyond the links, a pair of lever arms for each channel, meanspivotally securing each of the lever arms intermediate its ends torespective side walls, fifth pivot means securing the lever arms of onechannel to respective lever arms of the other channel and moveable in adirection from said line toward said first pivot means, whereby thelever arms project into respective channels for engaging the legs whenthe socket portions of the channels are spread apart.

References Cited in the file of this patent UNITED STATES PATENTS1,996,761 Gould et al. Apr. 9, 1935 2,105,979 Manley Jan. 18, 19382,545,767 Dalton t Mar. 20, 1951 2,555,503 Morton June 5, 1951 2,561,864Hollywood July 24, 1951

